On the thread topic as a whole, I think it's not necessary. The OGL has already allowed hobbyists to take up the banner of previous editions of D&D and produce new content. I just purchased an honest-to-goodness OD&D (1974) adventure... a compatible product, anyway... from Brave Halfling. Granted, it seemed like they must have been selling it at about cost, but that's fine. It's a hobby.
However, on this one point:
It's bad for WotC if new players have multiple D&Ds to choose from. It means that WotC is then forced to support multiple D&Ds in order to support the new gamers, and the cost of supporting multiple games is prohibitive if they're both aimed at the same general audience: The fantasy-focused RPGer.
I strongly disagree. At the peak of D&D's popularity you 2-3 separate versions of D&D available (Classic and AD&D 1e, and at times the OD&D OCE box).
I'm not against WOTC. But they seem to be going the Games Workshop route: you don't play role playing games, you play D&D (just like GW games aren't "wargames", they're "the Games Workshop hobby"). And when a new edition comes out, the old stuff is cast away and forgotten (though WOTC does sell old PDFs, which is excellent of them). Each edition, the game changes significantly and you have to rebuy a lot of stuff, including all new books. The magazine is not a hobby magazine but a house organ. And the whole thing becomes more narrow and self-referential... a universe of private IP rather than something expansive.
If you look through old stuff from SR / Dragon, you'll see that it was not always thus. There was stuff for other companies' games, stuff for multiple editions of the D&D game, stuff for other TSR products, all kinds of crazy stuff. You even had articles like the famous "Sturmgeschutz and Sorcery" for combining D&D with your WWII miniatures (which of course you have... at least you surely have Germans!).
It seems like the prevailing idea at WOTC is that D&D (4E here) is a very specific type of game. It does one thing and that is what you do with it. Everyone will play it basically the same way. D&D is a thing unto itself and has no external concerns.
And I suppose that leads to some people thinking that you shouldn't even really question it (4E), because there's no non-immanent standpoint from which to do so. You either accept it or you don't. Don't like something about the game? Then it isn't for you, etc.
And the inevitable business model repeats itself: churn out a billion products in the hopes that your hardcores buy basically every one, then reboot a few years later and start anew. I think that snake always ends up swallowing its own tail.